2023 · Bioengineering & translational medicine · open access
Microsampling tools for collecting, processing, and storing blood at the point-of-care
Baillargeon & Mace
The finding, in our words
Self-administered finger-stick blood collection enables routine healthcare assessments without clinic visits, but diagnostic utility depends critically on sample processing and storage. While new materials address haematocrit effects and enable precise low-volume sampling, no single device meets all clinical needs, and plasma separation remains essential for expanding applications.
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In AML and CLL, 91% of VAMS venetoclax results fell within 20% of plasma after individualised haematocrit correction; in home sampling, 18 of 21 patients self-sampled independently and 76% of returned samples were analysable, which shows home microsampling is workable, though the authors ask for multicentre validation.
This review found that volumetric microsampling devices, such as Mitra, HemaPEN, HemaXis DB10, and Tasso-M20, overcome haematocrit bias, whilst Telimmune plasma separation cards enable direct plasma collection without centrifugation. These technologies support patient-centric, decentralised sampling, though the authors note that clinical validation remains limited across different drugs and patient populations.
Capillary dried blood spots, after haematocrit-dependent conversion, showed good agreement with plasma for 25-hydroxyvitamin D quantification, with 90 per cent of results within 20 per cent of plasma and substantial to almost perfect agreement in status classification, supporting reliable home self-collection for large-scale vitamin D monitoring.
A machine learning model called Remote Control was trained on 2685 blood samples to predict change due to instability, enabling accurate calibration of results to approximate the time zero value at collection. With calibration, unprocessed whole blood could be transported for up to 9 days under ambient conditions and temperatures between 3.4 and 47.4 degrees Celsius, achieving agreement with CLIA TEa between 98.1 and 100 per cent and expanding the catalog of tests available for at-home collection.
Volumetric microsampling can enable patient-centred therapeutic drug monitoring with high patient preference and acceptable method validation for many drugs, but conversion from capillary to plasma and agreement with venous sampling varies by analyte and requires careful validation.